Trivial example of running assembled WebAssembly text in Node

blah.wast

(module
	(func $add (param $a i32) (param $b i32) (result i32)
		get_local $a
		get_local $b
		i32.add
	)
	(export "add" (func $add))
)

run-wasm.js

var fs = require("fs")

var binary = fs.readFileSync("blah.wasm")

var module = new WebAssembly.Module(binary)
var instance = new WebAssembly.Instance(module)

console.log(instance.exports.add(23, 45))

To Run

Clone the WABT repository and build it:

git clone https://github.com/WebAssembly/wabt.git
cd wabt
git submodule update --init
mkdir build
cd build
cmake ..
make

Ensure Node.js 8 (or later) is available on your path:

node --version

Download the files in the Gist into the build directory and assemble blah.wast:

./wat2wasm blah.wast

Run the JS loader in Node:

node run-wasm.js